Apparatus for calculating decision parameters in an IMT-2000 system

ABSTRACT

Improved techniques for calculating decision parameters in an IMT-2000 system, the IMT-2000 system having a mini-slot selection unit for selecting a mini-slot position wherein a decision parameter is selected and a decision parameter selection unit for selecting one decision parameter from the calculated decision parameters, is disclosed. In an apparatus for calculating decision parameters, there is provided a correlation value calculation unit having a number of correlation value calculators, each of which calculates a correlation value between selected information that is selected at the mini-slot selection unit and one of capable input signals. In order to selectively operate the correlation value calculators, there is provided a correlation circuit control unit controlling the operation of each of the correlation value calculators by using each of the comparison between the received correlation value to a predetermined threshold value; and a ranking determination unit receiving and ranking the correlation values and selectively operating the correlation value calculators according to the rank of the correlation values. Accordingly, the power consumption of the correlation value calculators is reduced. And, the decision parameter is selected from the decision parameters previously selected during the divided monitoring section, thereby enabling high-speed cell search.

FIELD OF THE INVENTION

[0001] The present invention relates to an apparatus for calculatingdecision parameters in an IMT-2000 system, and, more particularly, to anapparatus for calculating decision parameters with low power consumptionand a high-speed cell search.

DESCRIPTION OF THE PRIOR ART

[0002] Generally, at a code position modulation (CPM) type of W-CDMAsystem, a position of a synchronization signal (a synchronization code)which is used to perform a base station discrimination, a mobile stationsynchronization and a high-speed cell search, is differently modulatedaccording to each of base stations and transferred to each of receivers.

[0003] The synchronization code of a forward directional synchronizationchannel adapted by the CPM type consists of one binary code having alength of 256 chips. One synchronization code is transmitted accordingto each of slots. Wherein, one frame is a length of 2560 chips and oneframe has 16 slots. Each of the slots is divided into a number ofmini-slots. The length of the mini-slot is represented by δ that is apositive integer and a changeable parameter according to a need ofsystem operation.

[0004] In addition, the position of the synchronization code inserted toeach of the mini-slots is given to a value coinciding with each codeelement of a time hopping code corresponding to a long code group of acurrent base station. The length of the time hopping code used herein is16 being equal to the length of slot number of each frame. The magnitudeof alphabet M of each time hopping code is equal to or less than thenumber of mini-slots in a slot.

[0005] On the other hand, at a transmitting unit, the position of thesynchronization code adapted by the CPM type is modulated andtransmitted. A receiving unit (a CPM receiver) receives the modulatedand transmitted position and detects base station group information.

[0006]FIG. 1 shows a schematic diagram of a high-speed cell searchingprocess of a prior art of a CPM type of W-CDMA system.

[0007] At first step, a start point of a mini-slot is detected by usinga synchronization channel match filter.

[0008] And then, at second step, both long code group information and astart point of 10 ms frame are detected by using the output value of thematch filter at each mini-slot clock position (i.e., each δ chip) afterthe start point of the mini-slot.

[0009] Finally, the long code start point information is used todetermine the type of the long code.

[0010] The detailed description of the second step is as follows.

[0011] For example, in case that the number of the long code group usedat the system is 2 and the number of each of the slots is 4, a decisionparameter is calculated as follows.

[0012] Long code group number=2

[0013] Slot number per frame=4

[0014] Mini-slot number=Skip code alphabet magnitude=5

[0015] Skip code for group 1=(1 3 3 4)

[0016] Skip code for group 2=(4 2 0 1)

[0017] Total code/shift collection=(1 3 3 4) (4 1 3 3) (3 4 1 3)(3 3 41)(4 0 2 1)(1 4 0 2)(2 1 4 0) (0 2 1 4)

[0018] Time shift (slots)=0 1 2 3

[0019] As shown in above example, a CPM receiver calculates decisionparameters for 8 (2×4) code group shift collections based on the slotstart point of the matched filter. The decision parameters arecorrelation values between an input code and all of group informationcodes. The largest decision parameter is a group information code havinga largest capability. The group information code is used to calculate astart point of the frame.

[0020] For one mini-slot, L (Code group number×Slot number per frame)decision parameters are calculated. The mini-slot number N is determinedaccording to a required system performance and a used circumstance.

[0021]FIG. 2 shows a block diagram of a prior art of a CPM receiver.

[0022] As shown in FIG. 2, a mini-slot selection unit 10 selects asuitable mini-slot position at an inputted synchronization channel. Eachof the selected suitable mini-slot positions is provided to each ofdecision parameter calculators 21, 22 and 20+N contained at a decisionparameter calculation unit 20 through each of lines L2, L4 and L6.

[0023] Each of the decision parameter calculators 21, 22 and 22+Ncalculates a correlation value between each input and all of the groupinformation codes provided from line L8. Each output from each of thecalculators 21, 22 and 22+N is provided to a decision parameterselection unit 30.

[0024] The decision parameter selection unit 30 selects requiredinformation among the inputted decision parameters.

[0025] In general, the required information selected at the decisionparameter selection unit 30 is comprised of a set of several decisionparameters having a largest value. At this time, the decision parametercalculation unit 20 continues a calculation process that does not effectthe final decision parameter selection determination.

[0026] Since, however, the decision parameter calculation unit of theprior CPM receiver continues the calculation process after the decisionparameter selection unit selects the required information, a consumptionpower of the receiver is increased.

SUMMARY OF THE INVENTION

[0027] It is, therefore, a primary object of the invention to provide toan apparatus for calculating decision parameters with low powerconsumption and a high-speed cell search.

[0028] To achieve the above object, in one embodiment of the presentinvention, an apparatus for calculating decision parameters in anIMT-2000 system, the IMT-2000 system having a mini-slot selection unitfor selecting a mini-slot position wherein a decision parameter isselected and a decision parameter selection unit for selecting onedecision parameter from the calculated decision parameters, saidapparatus comprises: a correlation value calculation unit having anumber of correlation value calculators, each of which calculates acorrelation value between selected information that is selected at themini-slot selection unit and one of capable input signals; and acorrelation circuit control unit having a number of correlation circuitcontrollers each of which receives a correlation value from acorresponding one of the correlation value calculators and compares thereceived correlation value to a predetermined threshold value during apredetermined monitoring section, and controlling the operation of eachof the correlation value calculators by using each of the comparingresults.

[0029] Wherein, the predetermined monitoring section is obtained bydividing a total monitoring section of each of the correlation valuecalculators, and said threshold value is determined in order todetermine whether one of the correlation value calculators operates ornot during the total monitoring section.

[0030] To achieve the above object, in another embodiment of the presentinvention, an apparatus for calculating decision parameters in anIMT-2000 system, the IMT-2000 system having a mini-slot selection unitfor selecting a mini-slot position wherein a decision parameter isselected and a decision parameter selection unit for selecting onedecision parameter from the calculated decision parameters, saidapparatus comprises: a correlation value calculation unit having anumber of correlation value calculators, each of which calculates acorrelation value between selected information that is selected at themini-slot selection unit and one of capable input signals; and a rankingdetermination unit receiving each of correlation values provided fromeach of the correlation value calculators during a predeterminedmonitoring section, ranking the correlation values and selectivelyoperating the correlation value calculators according to the rank of thecorrelation values.

[0031] Wherein, the predetermined monitoring section is obtained bydividing a total monitoring section of each of the correlation valuecalculators, and wherein said ranking determination unit operates apredetermined number of high ranked correlation value calculators andstops the operation of the other correlation value calculators that arenot high ranked during a remaining total monitoring section.

[0032] The advantages of the invention are numerous. One of advantage ofthe invention is that a number of correlation value calculators that donot effect the decision parameter selection are not operated during theremaining monitoring section by using the threshold comparison techniqueand the correlation value ranking technique to reduce the powerconsumption of the correlation value calculators.

[0033] Another advantage of the invention is that the decision parameteris selected from the decision parameters previously selected during thedivided monitoring section, thereby enabling high-speed cell search.

[0034] These and other features of the present invention are more fullyshown and described in the drawings and detailed description of thisinvention. It is to be understood, however, that the description anddrawings are for the purpose of illustration and should not be read in amanner that would unduly limit the scope of this invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The above and other objects and features of the instant inventionwill become apparent from the following description of preferredembodiments taken in conjunction with the accompanying drawings, inwhich:

[0036]FIG. 1 is a schematic diagram of a high-speed cell searchingprocess of a prior art of a CPM type of IMT2000 system;

[0037]FIG. 2 shows a block diagram of a prior art of a CPM receiver ofIMT2000 system;

[0038]FIG. 3 describes a block diagram of a decision parametercalculation apparatus of IMT2000 system in accordance with a firstembodiment of the present invention; and

[0039]FIG. 4 illustrates a block diagram of a decision parametercalculation apparatus of IMT2000 system in accordance with a secondembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0040] Preferred embodiments of the present invention will now bedescribed in detail, with reference to the accompanying drawings.

[0041] The decision parameter calculation unit in accordance with thepresent invention utilizes a threshold value technique or a rankingtechnique.

[0042] <Embodiment 1>

[0043]FIG. 3 describes a block diagram of a decision parametercalculation unit of IMT2000 system in accordance with a first embodimentof the present invention.

[0044] As shown in FIG. 3, a reference numeral 100 denotes a correlationvalue calculation unit having a number of correlation value calculators101, 102 and 100+N. Each of the correlation value calculators 101, 102and 100+N calculates a correlation value between selected informationthat is selected at the mini-slot selection unit (reference numeral 10of FIG. 2) and one of capable input signals.

[0045] Also, a reference numeral 200 denotes a correlation circuitcontrol unit 200 having a number of correlation circuit controllers 201,202 and 200+N. Each of the correlation circuit controllers 201, 202 and200+N receives a correlation value from a corresponding one ofcorrelation value calculators 101, 102 and 100+N and compares thereceived correlation value to a predetermined threshold value during apredetermined monitoring section. By using each of the comparingresults, each of the correlation circuit controllers 201, 202 and 200+Ncontrols the operation of a corresponding correlation value calculator.

[0046] The operation of the first embodiment is as follows.

[0047] Firstly, each output from the mini-slot selection unit 10 of FIG.2 is provided to a corresponding one of correlation value calculators101, 102 and 100+N contained at the correlation value calculation unit100.

[0048] And then, each of the correlation value calculators 101, 102 and100+N calculates the correlation value between the inputted value andone of the capable input signals to provide the calculated correlationvalue to a corresponding one of the correlation circuit controllers 201,202 and 200+N contained at the correlation circuit control unit 200.

[0049] Each of the correlation circuit controllers 201, 202 and 200+Ncontained at the correlation circuit control unit 200 compares thepredetermined threshold value (H1) to an inputted correlation valueduring a divided monitoring section (T1) that is divided from a priormonitoring section (T). The threshold value is a value by which thecorrelation value calculator is operated or not during the monitoringsection (T).

[0050] In case that the inputted correlation value is larger than thethreshold value (H1), a corresponding correlation calculator is operatedduring the monitoring section (T). In case that the inputted correlationvalue is not larger than the threshold value (H1) during the dividedmonitoring section (T1), a corresponding correlation calculator is notoperated during a remaining section, i.e., the section between the T1and T.

[0051] For example, a correlation circuit controller 201 compares acorrelation value from the correlation value calculator 101 to apredetermined threshold value (H1) during a divided monitoring section(T1). In case that the correlation value is larger than the thresholdvalue (H1), the correlation circuit controller 201 enables thecorrelation value calculator 101 to be operated during the monitoringsection (T) . In case that the correlation value is not larger than thethreshold value (H1), the correlation circuit controller 201 enables thecorrelation value calculator 101 to be not operated during a remainingsection, i.e., the section between T1 and monitoring section (T).

[0052] Similarly, each of the remaining correlation circuit controllers202 and 2000+N performs the same operation as the correlation circuitcontroller 201.

[0053] Since, therefore, each of the correlation value calculators 101,102 and 100+N is selectively operated or not according to the thresholdvalue, only the correlation value calculators having a condition that adecision parameter is larger than the threshold value, operates duringthe monitoring section (T) and other correlation value calculatorshaving a condition that a decision parameter is not larger than thethreshold value, does not operate after the divided monitoring section(T1). Accordingly, the power is not consumed during the remainingmonitoring section between T1 and T to reduce the power consumption.

[0054] <Embodiment 2>

[0055]FIG. 4 illustrates a block diagram of a decision parametercalculation apparatus in accordance with a second embodiment of thepresent invention.

[0056] As shown in FIG. 4, a reference numeral 300 denotes a correlationvalue calculation unit having a number of correlation value calculators301, 302 and 300+N. Each of the correlation value calculators 301, 302and 300+N calculates a correlation value between selected informationthat is selected at the mini-slot selection unit (reference numeral 10of FIG. 2) and one of capable input signals.

[0057] Also, a reference numeral 400 denotes a ranking determinationunit that receives each of correlation values provided from each of thecorrelation value calculators 301, 302 and 300+N a, ranks thecorrelation values and selectively operates the correlation valuecalculators 301, 302 and 300+N according to the rank of the correlationvalues.

[0058] The operation of the second embodiment is as follows.

[0059] Firstly, each output from the mini-slot selection unit 10 of FIG.2 is provided to a corresponding one of correlation value calculators301, 302 and 300+N contained at the correlation value calculation unit300.

[0060] And then, each of the correlation value calculators 301, 302 and300+N calculates the correlation value between the inputted value andone of the capable input signals to provide the calculated correlationvalue to the ranking determination unit 400 and the decision parameterselection unit 30 of FIG. 2.

[0061] The ranking determination unit 400 ranks the inputted correlationvalues, each of which is calculated during a divided monitoring sectionT1, and operates I number of correlation value calculators that are highranked. The other correlation value calculators that are not highranked, are not operated.

[0062] For example, in case that there are five correlation valuecalculators #1, #2, #3, #4 and #5, the ranking is in a sequence #2, #3,#1, #5, #4 during the divided ranking section (T1), and the number ofthe correlation value calculators to be operated is 3, the rankingdetermination unit 400 operates three correlation value calculators #2,#3 and #1 during the monitoring section (T) and does not operate theremaining correlation value calculators #5 and #4 during the monitoringsection (T).

[0063] Since, therefore, each of the correlation values is detected andranked during the divided monitoring section (T1) and only apredetermined number of high ranked correlation value calculators isoperated during a remaining monitoring section, the power consumptioncan be reduced.

[0064] The advantages of the invention are numerous. Differentembodiments or implementations may yield one or more of the followingadvantages. One of advantage of the invention is that a number ofcorrelation value calculators that do not effect the decision parameterselection are not operated during the remaining monitoring section byusing the threshold comparison technique and the correlation valueranking technique to reduce the power consumption of the correlationvalue calculators.

[0065] Another advantage of the invention is that the decision parameteris selected from the decision parameters previously selected during thedivided monitoring section, thereby enabling high-speed cell search.

[0066] Although the preferred embodiments of the invention have beendisclosed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the inventionas disclosed in the accompanying claims.

What is claimed is:
 1. An apparatus for calculating decision parametersin an IMT-2000 system, the IMT-2000 system having a mini-slot selectionunit for selecting a mini-slot position wherein a decision parameter isselected and a decision parameter selection unit for selecting onedecision parameter from the calculated decision parameters, saidapparatus comprising: a correlation value calculation unit having anumber of correlation value calculators, each of which calculates acorrelation value between selected information that is selected at themini-slot selection unit and one of capable input signals; and acorrelation circuit control unit having a number of correlation circuitcontrollers each of which receives a correlation value from acorresponding one of the correlation value calculators and compares thereceived correlation value to a predetermined threshold value during apredetermined monitoring section, and controlling the operation of eachof the correlation value calculators by using each of the comparingresults.
 2. An apparatus as recited in claim 1 , wherein thepredetermined monitoring section is obtained by dividing a totalmonitoring section of each of the correlation value calculators.
 3. Anapparatus as recited in claim 1 , wherein said threshold value isdetermined in order to determine whether one of the correlation valuecalculators operates or not during the total monitoring section.
 4. Anapparatus for calculating decision parameters in an IMT-2000 system, theIMT-2000 system having a mini-slot selection unit for selecting amini-slot position wherein a decision parameter is selected and adecision parameter selection unit for selecting one decision parameterfrom the calculated decision parameters, said apparatus comprising: acorrelation value calculation unit having a number of correlation valuecalculators, each of which calculates a correlation value betweenselected information that is selected at the mini-slot selection unitand one of capable input signals; and a ranking determination unitreceiving each of correlation values provided from each of thecorrelation value calculators during a predetermined monitoring section,ranking the correlation values and selectively operating the correlationvalue calculators according to the rank of the correlation values.
 5. Anapparatus as recited in claim 1 , wherein the predetermined monitoringsection is obtained by dividing a total monitoring section of each ofthe correlation value calculators.
 6. An apparatus as recited in claim 1, wherein said ranking determination unit operates a predeterminednumber of high ranked correlation value calculators and stops theoperation of the other correlation value calculators that are not highranked during a remaining total monitoring section.